This invention relates to a process for engraving an image into a workpiece and, more particularly, to a method for engraving of an image into a die plate by utilizing a layer-by-layer removal of material from the workpiece between the surface of the workpiece and the deepest point of the engraving into the workpiece.
Today""s laser system technology utilizes a program software which translates artwork of a desired image into control signals. The signals are directed to a control assembly which focuses a laser beam onto a separate workpiece according to lines of the artwork. The engraving is carried out by thermal interaction between the laser beam and the workpiece. The finished workpiece may be a mold for embossed items.
Heretofore, if the depth of the engraved image in the workpiece was not constant, the variations in the depths of the image were addressed by increasing the power (watts) of the laser. This increase of power increases the depth of laser penetration into the workpiece and thus the depth of material removed. The need to vary the power leads to inefficient laser use as continuous power adjustments need be made during the laser engraving process.
I have invented a method, which more efficiently addresses the penetration of the laser into the workpiece according to various layers of penetration without the need to continuously adjust the laser power.
My method utilizes available computer and laser system technology, e.g., the FOBA-LAS F94 and F114 laser engraving system distributed by FOBA North America Laser Systems of Lee""s Summit, Mo., or similar galvo beam drive Nd:yag lasers. Such a system includes computer program technology, which converts lines on provided artwork to control signals. The control assembly, responsive to such signals, guides the laser beam along the separate workpiece in correspondence to lines on the provided artwork. My method presents to a galvo driven Nd:yag laser system a composite piece of artwork comprising a plurality of pieces of artwork which form the overall image desired for engraving into the workpiece. Each piece of artwork has lines appearing thereon which the laser system software converts into laser paths of material removal. Each piece of artwork corresponds to a layer of material in the workpiece between the surface of the workpiece and the deepest point thereof. The laser system program software reads these pieces of artwork in a sequential manner starting with the top layer of the workpiece and descending therefrom. Upon completion a three-dimensional image will be engraved into the workpiece. The use of the plurality of artwork pieces corresponding to material layers provides for a layer by layer removal of material from the workpiece which precludes the need to adjust laser power.
This above method is particularly used for engraving a three-dimensional image into a die plate/mold used for forming items having embossed images thereon.
It is accordingly a general object of this invention to provide a method of engraving a three-dimensional image having variously exposed sloped surfaces into a workpiece, e.g., a mold/die plate utilizing available laser system technology.
Another object of this invention is to provide a method, as aforesaid, which engraves an image into a workpiece utilizing a layer by layer removal of material from the workpiece.
A further object of this invention is to provide a method, as aforesaid, which precludes the need to continuously adjust the laser beam power during engraving of the workpiece.
Another object of this invention is to provide a method, as aforesaid, which utilizes a plurality of pieces of artwork comprising the desired image at selected dimensions to be engraved into the workpiece with each piece of artwork corresponding to a layer of material to be removed from the workpiece.
Still another object of this image is to provide a method, as aforesaid, which can be performed utilizing available computer technology for providing the artwork pieces.
A further object of this invention is to provide a method, as aforesaid, which increases the efficiency of use of a laser engraving system.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.